I've only ever replace the bottom one (dogbone) with a stiffer one (MMMUUCCCHHH nicer with that in there, but it does shake) and for $25 shipped, the poly inserts are where its at. I have replaced the drivers side, and that took all of 5 mins after the air box was out of the way. The passenger side should be more fun....PM your phone number, I could be getting out of work early today (not much going on here today....)